Research And Design Of A700V High Voltage LED Driver IC

Smart Power integrated circuit (Smart Power IC) has been widely used in the highvoltage driver chips. With the development of integrated circuit,Although traditionaldiscrete high-voltage device has its important function, low voltage control logic andthe high voltage DMOS manufacture in one monolithic integrated circuit has become adevelopment trend. LED lighting is especially pronounced in civilian applications.Indoor lighting, outdoor neon signs, billboards, television, computer backlight and so onmany occasions, is inseparable from the LED lighting equipment. The advantage of ledin the color saturation, brightness, etc, is unmatched by traditional incandescent lamp.And on the power consumption, the traditional incandescent lamp can direct access to220v civil power grid, and the working voltage of LED is only a few volts, and theworking current is only several hundred microampere. Its power consumption is onlydozens or even one percent of traditional incandescent lamp. Because of its workingvoltage is only a few volts, how to make the LED equipment working in a normal andstable status become a problem that have to solve. Due to this, the work need morecomplex conversion circuit, which is also called LED driver circuit. Traditional LEDdriver chip used in high voltage device for ordinary LDMOS device, which canwithstand high voltage, and for civil LED driver chips, the working voltage requires thechip can withstand at least330V. This has led to its large chip area, and long drift region.And make the chip has a high resistance, and high power consumption.Mainly work of this essay is based on BCD technology platform, and havedeveloped a LED driver circuit that can be realized. By Changing the high-voltagedevice structure, optimizing the performance of device, promoting the withstand voltage,reducing the on-resistance, this work has reduced the power consumption of LED. Theinternal REGULATOR module produces a working voltage of7.5V, the Vref moduleproduces a reference voltage, the compare module compare tow voltage to control theon-and-off time order of LDMOS, and relatively stable working current is obtained. High-voltage device module is presented in this paper, by discussing the performance ofdifferent structures, including triple RESURF device, partial buried layer device, andflower RESURF device. The analog contains five modules, including UVLO module,REGULATOR module, Vref module, Iref module and Logic module. And externalcircuit includes four diode rectifier bridge, diodes and capacitors to obtain dc current.Though high voltage device to sampling the current, though REGULATOR module toobtaining7.5V working voltage, through Vref module to obtaining1.25V referencevoltage, through Iref module to obtaining the control signal, and through Logic moduleto obtaining the gate control signal of LDMOS.